1 files changed, 202 insertions, 0 deletions
diff --git a/dom/media/MediaShutdownManager.cpp b/dom/media/MediaShutdownManager.cpp
new file mode 100644
index 0000000000..4a3c3a4357
--- /dev/null
+++ b/dom/media/MediaShutdownManager.cpp
@@ -0,0 +1,202 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaShutdownManager.h"
+
+#include "MediaDecoder.h"
+#include "mozilla/Logging.h"
+#include "mozilla/media/MediaUtils.h"
+#include "mozilla/Services.h"
+#include "mozilla/StaticPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIWritablePropertyBag2.h"
+
+namespace mozilla {
+
+#undef LOGW
+
+extern LazyLogModule gMediaDecoderLog;
+#define DECODER_LOG(type, msg) MOZ_LOG(gMediaDecoderLog, type, msg)
+#define LOGW(...) NS_WARNING(nsPrintfCString(__VA_ARGS__).get())
+
+NS_IMPL_ISUPPORTS(MediaShutdownManager, nsIAsyncShutdownBlocker)
+
+MediaShutdownManager::MediaShutdownManager() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_DIAGNOSTIC_ASSERT(sInitPhase == NotInited);
+}
+
+MediaShutdownManager::~MediaShutdownManager() { MOZ_ASSERT(NS_IsMainThread()); }
+
+// Note that we don't use ClearOnShutdown() on this StaticRefPtr, as that
+// may interfere with our shutdown listener.
+StaticRefPtr<MediaShutdownManager> MediaShutdownManager::sInstance;
+
+MediaShutdownManager::InitPhase MediaShutdownManager::sInitPhase =
+    MediaShutdownManager::NotInited;
+
+MediaShutdownManager& MediaShutdownManager::Instance() {
+  MOZ_ASSERT(NS_IsMainThread());
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  if (!sInstance) {
+    MOZ_CRASH_UNSAFE_PRINTF("sInstance is null. sInitPhase=%d",
+                            int(sInitPhase));
+  }
+#endif
+  return *sInstance;
+}
+
+void MediaShutdownManager::InitStatics() {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (sInitPhase != NotInited) {
+    return;
+  }
+
+  sInstance = new MediaShutdownManager();
+  MOZ_DIAGNOSTIC_ASSERT(sInstance);
+
+  nsCOMPtr<nsIAsyncShutdownClient> barrier = media::GetShutdownBarrier();
+
+  if (!barrier) {
+    LOGW("Failed to get barrier, cannot add shutdown blocker!");
+    sInitPhase = InitFailed;
+    return;
+  }
+
+  nsresult rv =
+      barrier->AddBlocker(sInstance, NS_LITERAL_STRING_FROM_CSTRING(__FILE__),
+                          __LINE__, u"MediaShutdownManager shutdown"_ns);
+  if (NS_FAILED(rv)) {
+    LOGW("Failed to add shutdown blocker! rv=%x", uint32_t(rv));
+    sInitPhase = InitFailed;
+    return;
+  }
+  sInitPhase = InitSucceeded;
+}
+
+void MediaShutdownManager::RemoveBlocker() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_DIAGNOSTIC_ASSERT(sInitPhase == XPCOMShutdownStarted);
+  MOZ_ASSERT(mDecoders.Count() == 0);
+  nsCOMPtr<nsIAsyncShutdownClient> barrier = media::GetShutdownBarrier();
+  // xpcom should still be available because we blocked shutdown by having a
+  // blocker. Until it completely shuts down we should still be able to get
+  // the barrier.
+  MOZ_RELEASE_ASSERT(
+      barrier,
+      "Failed to get shutdown barrier, cannot remove shutdown blocker!");
+  barrier->RemoveBlocker(this);
+  // Clear our singleton reference. This will probably delete
+  // this instance, so don't deref |this| clearing sInstance.
+  sInitPhase = XPCOMShutdownEnded;
+  sInstance = nullptr;
+  DECODER_LOG(LogLevel::Debug, ("MediaShutdownManager::BlockShutdown() end."));
+}
+
+nsresult MediaShutdownManager::Register(MediaDecoder* aDecoder) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (sInitPhase == InitFailed) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  if (sInitPhase == XPCOMShutdownStarted) {
+    return NS_ERROR_ABORT;
+  }
+  // Don't call Register() after you've Unregistered() all the decoders,
+  // that's not going to work.
+  MOZ_ASSERT(!mDecoders.Contains(aDecoder));
+  mDecoders.Insert(aDecoder);
+  MOZ_ASSERT(mDecoders.Contains(aDecoder));
+  MOZ_ASSERT(mDecoders.Count() > 0);
+  return NS_OK;
+}
+
+void MediaShutdownManager::Unregister(MediaDecoder* aDecoder) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!mDecoders.EnsureRemoved(aDecoder)) {
+    return;
+  }
+  if (sInitPhase == XPCOMShutdownStarted && mDecoders.Count() == 0) {
+    RemoveBlocker();
+  }
+}
+
+NS_IMETHODIMP
+MediaShutdownManager::GetName(nsAString& aName) {
+  aName = u"MediaShutdownManager: shutdown"_ns;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MediaShutdownManager::GetState(nsIPropertyBag** aBagOut) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aBagOut);
+
+  nsCOMPtr<nsIWritablePropertyBag2> propertyBag =
+      do_CreateInstance("@mozilla.org/hash-property-bag;1");
+
+  if (NS_WARN_IF(!propertyBag)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  nsresult rv = propertyBag->SetPropertyAsInt32(
+      u"sInitPhase"_ns, static_cast<int32_t>(sInitPhase));
+
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  nsAutoCString decoderInfo;
+  for (const auto& key : mDecoders) {
+    // Grab the full extended type for the decoder. This can be used to help
+    // indicate problems with specific decoders by associating type -> decoder.
+    decoderInfo.Append(key->ContainerType().ExtendedType().OriginalString());
+    decoderInfo.Append(", ");
+  }
+
+  rv = propertyBag->SetPropertyAsACString(u"decoderInfo"_ns, decoderInfo);
+
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  propertyBag.forget(aBagOut);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MediaShutdownManager::BlockShutdown(nsIAsyncShutdownClient*) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_DIAGNOSTIC_ASSERT(sInitPhase == InitSucceeded);
+  MOZ_DIAGNOSTIC_ASSERT(sInstance);
+
+  DECODER_LOG(LogLevel::Debug,
+              ("MediaShutdownManager::BlockShutdown() start..."));
+
+  // Set this flag to ensure no Register() is allowed when Shutdown() begins.
+  sInitPhase = XPCOMShutdownStarted;
+
+  auto oldCount = mDecoders.Count();
+  if (oldCount == 0) {
+    RemoveBlocker();
+    return NS_OK;
+  }
+
+  // Iterate over the decoders and shut them down.
+  for (const auto& key : mDecoders) {
+    key->NotifyXPCOMShutdown();
+    // Check MediaDecoder::Shutdown doesn't call Unregister() synchronously in
+    // order not to corrupt our hashtable traversal.
+    MOZ_ASSERT(mDecoders.Count() == oldCount);
+  }
+
+  return NS_OK;
+}
+
+}  // namespace mozilla
+
+// avoid redefined macro in unified build
+#undef LOGW